Alarm for typewriters



April 18, 1933. w, F, MANN l ALARMFOR 'YPEwRITERs Filed July '7, 1930 v v l `nvenlor MLU/104m MAY/VQ v i By' ma v v r A ttorney Patented pr. 18, 1933 UNITED STATES WILLIAM F. n. MANN, or NEW Yonx, N. Y.

ALARM FOR TYTEWRITERS Application led J'uly 7, 1930. Serial No. 466,327.

This invention relates to improvements in 4 alarms or signals for typewriters, and it pertains particularly toa device for giving to the operator of a typewriting machine, an

alarm or signal to indicate to the operator that the bottom edge of the sheet is nearing the writing position, and should be removed from the machine.

It is an object of the invention to provide an alarm device which may be adjusted to adapt it .to use with sheets of different lengths, such for example, as letter size sheets, legal size sheets, etc.

A further object of the invention resides n? in the provision of means by which although the device may be readily detached with respect toa typewriting machine, it will at the 'same time be rmly held in its operative position on the machine.

'A feature of the invention resides in the provision of an alarm operating means which is actuated by the movement of the typewriter platen and which is adjustable relatively thereto and to the alarm actuating means, whereby to vary the operation of the alarm, relative to the platen of the machine.

Another feature of the invention resides in the provision of means whereby the platen 'of the typewriting machine may be operated in either direction without injury to any of the parts of the alarm device.

Other features of the invention relate to certain novel and improved constructions, arrangements and combinations of parts hereinafter described and particularly ointed out in the claims, the advantages o which will be readily understood and appreciated by those skilled in the art.

The invention will be clearly understood from the accompanying drawing illustrating the invention in its preferred form, and the following detailed description of the con'- structions therein shown.

In the drawing, v

Figure 1 is a view partly in section, and

partly in end elevation of the platen of a typewriting machine, the attachment being shown in position thereon;

Figure 2 is a view partly in elevation and partly in section taken at right angles to w igure 1;

Figure 3 is a detail plan view; and

Figure 4 is a verticalsectional `view taken on an enlarged scale.

In the drawing, 5 designates the platen of 55 a typewriting machine, and 6 illustrates conventionally an end plate of the machine frame. A device constructed in accordance with the present invention is preferably supported by a plate such as 7 which as herein shown is substantially tri-angular in form, and is provided with two depending hooks 8 and 9 at the lower terminations or ends of, legs 10 and 11 respectively.- The hook 9 is pivotally mounted on the plate as at 12 and 65 is provided with an operating thumb piece 13. Connected as at 14 to the plate and as at 15 to the pivoted hook member 9, there is a spring 16 which returns the hook member-9 to normal position.

While the foregoing describes the attachment of the device to the machine as illustrated herein, it is to be understood that this specific form of attachment is not used in all cases, and that the plate7 may vary in its shape dependent upon the type of machine to which the device is to be attached and that all of this may be done without departing from the spirit of the invention.

The platen roller 5 has the ordinary shaft 80 17 extending through the plate 6', and is provided on its free end with an operating knob 18.

In carrying out the present invention, a gear 20 is mounted upon the platen roller shaft 17, and this gear 20 meshes with/a gear 21 mounted on the plate 7 vwhich in turn meshes with a gear 22 carried on a stub shaft 23 which in turn is mounted as at 24 in the plate 7., rlhis gear 22 is of considerably 90 larger diameter than the gears and 21, and it is to be understood that this gear 22 is of such diameterthat it will make one revolution to the proper number of revolutions of the platen roller 5 to feed a relatively long sheet of paper such as legal size through the machine, this result bein accomplished by a proper ratio between t e gears 20 and 21 and the gear 22.

The gear 22 is rovided on its outer face with a plurality o rack teeth 24', and. mounted on the stub shaft 23, there is a resilient arm 25 which is adapted to engage the rack teeth 24 when in its normal position. Carried by the member 25, there isa pivoted trigger or like member 26 which is held normally in the position in which it is shown in Figures 2 and 4 by means of a 'spring 27. rlhis member 26 is adapted to operate a bell tapper 28 carried by a resilient arm 29 which in turn is mounted upon the stub shaft 23. rlhe tapper 28 is mounted internally of a bell 30 which is carried by the stub shaft 23, and the trigger 26 heretofore mentioned projects inwardly of the bell and into the path of the tapper 28. y

Thus it will be seen that as the gear 22 is driven by operation of the platen roller 5 in the ordinary operation of the typewriter machine to which the device is attached, and the gear 22 makes va complete revolution in a clockwise direction in Figure 1, the arm 26 will engage the tapper'28 as illustrated in Figure l, and will move the same by flexingl its resilient spring 29 until the tapper 28 is snapped by the trigger member 26 upon continued movement of the gear 22 and engages the bell 30 to cause an alarm.

ln Figure 1, the trigger 26 is illustrated in the action of just releasing the bell tapper 28, and it will be noted that the bell tapper when released will engage a projection 31 to sound the alarm, after which the resilient member 29 maintains the tapper 28 in enga ement with the projection 31 to prevent vi ration of the tapper against the bell during operation of the machine, thus insuring quiet 'operation of the device.

As will be noted by reference to Figure 3, the bell 30 may be provided with a plurality of indications 32, which may serve as indication points of adjustment for the member 25 in order'that the same may be positioned with relation to the size of sheet being used, this insuring operation of the alarm at the proper moment for each length of sheet being used.

To prevent injury to the several parts of the machine bv quickly reverse operation of the platen of the typewriter, the trigger is so mounted that when moved in the reverse, or anti-clockwise direction, it swings around the member 25 upon which it is mounted, against the 'tension of the spring 27 as it engages the member 22, and immediately the trigger 26 passes by the member 29, the spring 27 returns the trigger 26 to operating position. A suitable stop is provided to prevent movement of the trigger 26 in the opposite direction and thereby msures operation of the bell tapper when the platen is turned in proper paper feeding direction.

From the foregoing it will be apparent that the present invention provides a novel signal or alarm which will effectively indicate the approach to the bottom of a sheet of paper being written upon by a typewriting machine, and at the same time, the device of the present invention provides for ad justment whereby the operation may be regu lated for various sizes of letter sheets.

While the invention has been herein illustrated in a preferred form, it is to be understood that it is not to be limited to the form herein shown, and that it may be illustrated in other forms which rightfully fall within the scope of the appended claims.

Having thus described the invention, what is claimed as new and desired to secure by U. S. Letters Patent, is:

1. A typewriter attachment -including a rotatably mounted gear wheel provided on one face thereof with a series of rack teeth, additional gear wheels for driving the first named gear ,wheel from the platen of the typewriter, an audible signal including a tapper and a resilient support therefor, and actuating means for the'tapper comprising an arm arranged to rotate on an axis coincident with the axis of the first named gear wheel, and being also adapted to engage said rack teeth to thereby rotate with said first named gear wheel, and a spring return l trigger pivotally mounted on said arm and arranged to engage said resilient tapper sup-- port and thereby actuate said signal.

2. lin a device of the character described, a bell, a tapper therefor, and a resilient support for the tapper; supporting means for the bell adapted to be detachably connected with a typewritino machine and including a stub shaft, a meniber rotatably mounted on 'the stub shaft, motion transmitting means operatively connecting said rotatable member with the platen of the typewritng machine, an arm rotatably mounted on said stub shaft, teeth on said rotatable member arranged to engage said arm to cause the latter to rotate with said rotatable member, and a trigger device carried by said arm and arranged to engage and actuate the said tapper for sounding the bell.

ln testimony whereof I aiiiX my signature.

WlLLlM F. H. MANN. 

